Cosmologists at Perimeter Institute seek to help pin down the constituents and history of our universe, and the rules governing its origin and evolution. Many of the most interesting clues about physics beyond the standard model (e.g., dark matter, dark energy, the matter/anti-matter asymmetry, and the spectrum of primordial density perturbations], come from cosmological observations, and cosmological observations are often the best way to test or constrain a proposed modification of the laws of nature, since such observations can probe length scales, time scales, and energy scales that are beyond the reach of terrestrial laboratories.
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Growing large SMBH at early times with dissipative dark matter
Akshay Anant Ghalsasi
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The matter-era distance excess
Zach Weiner - Perimeter Institute for Theoretical Physics
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Illuminating the growth of cosmic structure with DESI
Alex Krolewski - University of Waterloo
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Hawking Radiation from near extremal black holes
Mykhaylo Usatyuk
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Imprints of Cosmic Topology from Early-Universe Quantum Effects
Anna Negro - Case Western Reserve University
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Can the radiation era extend back to the bang?
Vatsalya Vaibhav - Higgs Centre for Theoretical Physics, University of Edinburgh
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Confronting cosmological tensions through precision CMB lensing
Frank Qu - KIPAC
The cosmic microwave background (CMB) serves as a unique backlight for tracing the growth of cosmic structures. By measuring arc-minute-scale deflections experienced by CMB photons due to gravitational lensing, we can map matter distributions at high redshifts. This lensing signal provides a… -
Field-level forward modelling with a physical, non-local stochastic galaxy-bias model calibrated to hydrodynamical simulations
Maximilian von Wietersheim-Kramsta - Durham University
Galaxy positions and shapes, as tracers of the large-scale structure of the Universe, are key observables for testing cosmological models in the late Universe and into the non-linear regime. In this context, multi-scale baryonic dynamics, and their evolution over time, can have considerable effects… -
Relativistic Effects in the 3D Galaxy Power Spectrum
The three-dimensional galaxy power spectrum is a powerful probe of local primordial non-Gaussianity (PNG) and linear-order general relativistic (GR) effects on ultra-large scales, accessible to current large-scale structure surveys. In this talk, we present our calculation of GR effects in the… -
Infant Black Holes in the Early Universe
Roberto Maiolino
Recent years have seen remarkable progress in the exploration of black holes in the early Universe, including the discovery of hundreds of accreting black holes within the first few billion years after the Big Bang. Many of these distant objects do not appear to be simple extrapolations of the local… -
Growing large SMBH at early times with dissipative dark matter
Akshay Anant Ghalsasi
Observations by JWST have indicated the presence of large SMBH within the first 500 Myr of the universe. The existence of these black holes require the BH seeds to grow faster than allowed by the Eddington limit. In this talk I will consider the growth of these black holes if a small component of… -
The matter-era distance excess
Zach Weiner - Perimeter Institute for Theoretical Physics
Observations of the cosmic microwave background and galaxy clustering are putting increasing pressure on the standard cosmological model, with surprising implications for massive neutrinos, dark energy, and nonminimal dark sectors more generally. I will present a general description of the tension… -
Illuminating the growth of cosmic structure with DESI
Alex Krolewski - University of Waterloo
In this talk, I will describe how DESI’s precise measurements of the large-scale galaxy distribution test our understanding of the standard cosmological model and probe the Universe’s initial conditions. First, I will show how DESI can measure the Hubble constant in several different ways… -
Cosmology with DESI DR2: From BAO to Full-Shape Clustering
The Dark Energy Spectroscopic Instrument (DESI) is mapping the large-scale structure of the Universe with unprecedented precision, opening a new window on cosmic expansion and the growth of structure. In this talk, I will give a brief introduction to the DESI survey and highlight recent results from… -
Hawking Radiation from near extremal black holes
Mykhaylo Usatyuk
Over the last few years it has been understood that black holes sufficiently close to extremality receive large quantum corrections that modify their thermodynamic properties. In this talk I will explain how these large quantum corrections modify the real time dynamics of near-extremal black holes… -
Holographic phase transitions via thermally-assisted tunneling
Arpon Paul
We construct the thermal bounce solution in holographic models that describes first-order phase transitions between the deconfined and confined phases in strongly-coupled gauge theories. This new, periodic Euclidean solution represents transitions that occur via thermally-assisted tunneling and… -
Imprints of Cosmic Topology from Early-Universe Quantum Effects
Anna Negro - Case Western Reserve University
Is the Universe infinite in all spatial directions? The answer may lie in the interplay between cosmic topology and quantum effects in the early universe. There are eighteen distinct topologies compatible with spatially flat Friedmann-Lemaître-Robertson-Walker solutions of Einstein’s equations… -
Can the radiation era extend back to the bang?
Vatsalya Vaibhav - Higgs Centre for Theoretical Physics, University of Edinburgh
Recent work has shown that a cosmological model in which the radiation era extends back to the Big Bang, with CPT-symmetric initial conditions, can provide a minimalistic explanation for many of the observed features of the early universe (homogeneity, isotropy, flatness, the CMB acoustic…